Pump



Aug. 22, 1933.

A. V. JENSEN PUMP Filed Jan. 9, 1931 3 Sheets-Sheet 1 INVENTOR. AMOSV JENSEN j W 2 W Ear ATTORNEYS JENSEN NVENTOR.

- AMOS.l/. JE/VSM fluww r'jm 3 Sheets-Sheet 2 Filed Jan. 9, 1931 ATTORNEYS Aug. 22, 1933. A v ENS N' 1,923,268

PUMP

Filed Jan. 9, 1931 3 Sheets-Sheet 3 INVENTQR. A/vms M JENSEN 5mm r M A TTORNEYS Patented Aug. 22, '1933 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to rotary pumps and more particularly to an opposed piloted impeller rotor pump.

An impeller rotor type of pump usually comprises a pair of intermeshing impeller rotors by means of which the liquid is pumped, which in turn are rotated byv a pair of pilot gears. Much difliculty has been encountered with the impeller rotor type of pump owing to the entrapment of liquid between the intermeshing rotor teeth. Since'liquids such as water and oil are non-compressible the liquid that is entrapped between the intermeshing rotors creates a very heavy thrust on the pump bearings which unevenly wears and distorts them so that the accuracy of the intermeshing of the impeller rotor teeth is destroyed. This necessarily gradually decreases the efficlency of the pump by permitting liquid to leak' past the intermeshed impeller rotors.

It is an object of this invention to eliminate this entrapment of the liquid and reduce substantially all leakage of the same past the impeller rotors and this has been achieved by providing a pair of impeller teeth which at all times have a continuous area of contact so that no chance for entrapment and/or leakage is permitted. 7

It is a further object of this invention to prevent churning and turbulence of the intake liquid and prevent the same from traveling in a direction opposing that of the impeller rotors so that the liquid will be prevented from colliding with the rotors and decreasing the volumetric and mechanical efficiency of the pump. This has been achieved by constructing the intake of the pump so that liquid is made to flow in substantially the same direction as the path of travel of the impeller rotor teeth. Hence, substantially all clashing of the intake liquid with the impeller rotor teeth is avoided.

It is a further object of this invention to .produce a pump in which the impeller rotors have a maximum intermesh to consequently obtain a maximum capacity.

In the drawings;

Fig. 1 is an elevation of the pump from the intake end.

Fig. 2 is a side elevation of the pump with a portion of the housing removed.

Fig. 3 is an elevation of the complete pump from the exhaust end.

Figs. 4, 5, and 6 are sectional and diagram matic views of the impeller rotor teeth in the various positions they assume in turning at 15 intervals.

Figs. '7 and 8 are detail views of the rubber seal container and the rubber seal respectiv ly used with the impeller teeth.

Figs. 9 and 10 are. illustrative views of a pump of the prior art inserted for descriptive purposes only.

'Fig. 11 is an elevation partly broken away showing a specific application of a pump to a fire fighting apparatus with a modified form of stream diverter.

Fig. 12 is an end. elevation of the pump shown in Fig. 11.

Fig. 13 is a section along the line 12--12 of Fig. 11.

Referring more particularly to the drawings, it will -be seen that the pump comprises a main housing 1 having a base portion 2, a discharge port 3, and an intake port 4. The main housing 1 is closed by the end housings 5 and 6. The pump is of the opposed impeller rotor type and hence is provided with the two impeller rotors '7 and 8. The impeller rotors .7 and 8 are mounted on the shafts-9 and 10- respectively. The shafts 9 and 10 are suitably journaled in the ends of the housing asat 11 and 12 respec tively. The opposite ends of the shafts 9 and 10 are suitably journaled in the end portion 6 of the housing and have fixed thereon the piloting gears 13 and 14' which in turn are operatively connected with the driving shaft 15.

In Fig. 9 there is shown one of the commonly used pumps of the prior art which broadly con- 'sists of the pump housing 16 having the intake port 17, the discharge port 18, and the impeller gears 19 and 20. The impeller gears 19 and 20 rotate in the direction indicated by the arrows. Hence, as the liquid flows through the intake port 17 through the housing, a certain portion of it clashes with, and retards the motion of, the impeller gears, owing to the fact that the impeller gears are' traveling in substantially the opposite direction of or actually against the direction of the incoming stream, and hence, a 1m turbulence and churning is set up which decreases the efliciency of the pump. Further, as brought out in Fig. 10, a portion of the liquid is entrapped as at 21 and 22 between the intermeshing teeth of the gears 19 and 20. liquid is substantially non-compressibla this obviously places a very great thrustupon the shaft bearings and eventually wears them away and distorts them so that the gears 19 and 20 no longer accurately intermesh and consequently 119 Since 1% the liquid leaks past the intermeshing gear teeth.

To obviate this difficulty the rotors 7 and 8. have been so designed that at all times the rotors contact along a progressive continuous area. By referring to Fig. 10 it will be seen that the gear teeth 23, 24, and 25 contact along two spaced areas as at 26 and 27 which in turn form a sump forthe collection of a certain amount of liquid as at 22. In other words, the gear teeth 23 and 25 .function in a manner analogous to a cylinder and piston with the gear tooth 24 serving as a plunger and in turn entrapping the liquid as at 22. This undesirable entrapment can be prevented by eliminating spaced areas of contact such as 26 and 2'7 and making the contact area progressively continuous.

In Figs. 2, 4, 5, and 6 this continuous contact area of the impeller rotors '7 and 8 is nicely brought out. In Fig. 4 the rotors have rotated in the direction of the arrows 15, in Fig. 5, 30, and in Fig. 6, 45 from the position of the gears shown in Fig. 2. It will be noted that the contact 28 of the intermeshing rotors'is at all times along one progressively continuous, non-intermittent area in contra-distinction to the spaced areas of contact 26 and 2'7 of the impeller gear teeth shown in Fig. 10. This continuous contact 28 at all times prevents the entrapment of any liquid between the rotor teeth because spaced areas of contact are necessary to entrapment of the liquid of the impeller rotors.

It is understood that any type of impeller rotors may be used which have a single contiuous area of contact, and for purposes of description only there is shown a specific form of impeller rotor having three teeth. This specific form of tooth is obtained as follows: In Fig. 2 the centers of rotation 29 and 30 are located at an assumed distance of six inches. With points 29 and 30 .as centers, the outer circumference of the rotor is described along a radius of four inches. A root diameter as shown is next described along a radius of two inches. A mean circumference is next described along a radius of three inches. A straight line is drawn between centers 29'and 30 and with 29 as a center the are 31-32 is described on the outer circumference of the rotor '7. Next the angle CD of 60 is laid out with center 30 as the apex. The line 30-D intersects the outer circumference of the rotor '7 at the tip of the tooth 33 as at 34. Next an are having its center on the center line of tooth 33 is struck which is tangent to the outer circumference of the impeller tooth rotor '7 as at 34 and to the are 31-32 as at 32. Next the impeller rotor '7 is rotated about its center 30 in the direction of the arrow and generates the curve 31-35 included between the angle A-B which is a 60 angle. Each'tooth comprises on the one side the curve 31-32-34 and on the other side the generated curve 31-35. It is understood, of course, that the outer, mean, and root diameters can be varied to obtain different sized rotors, but all of which intermesh along a single, progressively continuous area of rolling and sliding contact.

Since it is an object of this invention to, prevent interference of the incoming liquid with the motion of the impeller rotors and to prevent churning and turbulence of the liquid at the intake, to this end the intake 4 is provided with a stream diverter 40. The stream diverter 40 is positioned centrally of the intake 4 and substantially mid-way of the center of rotation of the two impeller rotors. The stream diverter is preferably wedge-shaped in crosssectionr The upper face 41 and the lower face 42 gradually diverge inwardly to direct the flow of the incoming liquid as shown by the arrows. This diversion of the faces 41 and 42 of the stream diverter divides and leads the incoming liquid in a direction substantially tangential to the path of rotation of the rotors. The sides of the intake port 4 are curved as at 43 and 44 so as to be substantially co-related with, the faces 41 and 42 respectively of the stream diverter. Thus the faces 41 and 43 divert their portion of the intake fluid in the direction indicated by the arrows and effectively prevent the incoming liquid from striking the rotors mid-way of their centers of rotation. The faces 42 and 44 function in a similar manner. It will be noted that the direction of the liquid as indicated by the arrows owing to the action of the stream diverter and cooperating faces 43 and 44 of the intake port, is never directly opposed to that of the'unmeshing impeller rotors with which it contacts and is in general tangential to the path of rotation of the gears.

By referring to Fig. 4 it will be seen that the path of the rotor tooth 45, the rotor rotating counter-clockwise as indicated by the arrow, is substantially opposed to .the direction of the flow of the incoming liquid but the stream diverter 40 effectively diverts the infiowing stream from conflicting with this tooth until it has swung about the axis of rotation sufficiently to begin its travel in the direction which the incoming liquid is made to fiow.

To further effectively seal the engagement of the impeller gear teeth with the housing and with each other, each tooth is provided with a rubber seal 60 (Fig 8) which is fixed and seated in a bifurcated cylindrical seal retainer 61. Each tooth is drilled as at 62 for the reception of the seal retainer 61 and provided with a. radial slot 63 for the rubber seal 60. The rubber seal 60 projects slightly beyond the outside circumference of the gear tooth. After the contact face of the rubber seal 60 wears away the seal retainer 61 and the rubber seal 60 can be readily removed and a new seal retainer and seal inserted in its place. The resilience of the rubber 60 effectively reduces the wearing away caused by grit and other foreign substances brought in with the liquid.

In operation the liquid stream enters the pump housing through the intake port 4 where it is divided and diverted, as indicated by the arrows, substantially tangential to the path of rotation of the impeller rotors by the stream diverter 40. As the rotors rotate in the direction of the arrows, the intake liquid is entrapped between the housing and each two successive rotor teeth and carried around by the rotating intermeshing impeller rotors and ejectimpeller rotors and at the same time substantially none of the liquid is permitted to escape past the intermeshing rotors into the intake area. Further the rubber seals effectively seal the contact between the housing and the impeller gears and between the intermeshing impeller gears.

In Figs. 11 to'13 there is shown a pump having a modified form of stream diverter. In these figures there is shown a pump that'is specifically adapted for fire fighting apparatus and which is arranged to be mounted upon a fire truck (not shown). This pump apparatus comprises the right intake pipe and the left intake pipe81, the right outlet pipe 82 controlled by the valve 83, and the left outlet pipe 84 controlled by the valve 85. The intake and outlet pipes have positioned therebetween the pump housing 86 with the impeller gears and associated operating mechanism generally referenced 87. The pump, that is, the housing, the impeller rotors, piloting gears, and driving shaft are similar to that above described, and hence, will not be described here.

With this type of pump the fire fighting truck drives up to the water supply hydrant. hydrant happens to be on the right the intake 80 is connected to the supply hydrant by means of the coupling 88 and if the fire is also on the right, then a suitable fire hose (not shown) is connected to the outlet pipe 82 by the coupling 89. If the fire is on the left then a suitable fire hose is connected to the left outlet pipe 84 by the coupling 90. In case the water supply hydrant is. on the left, then the intake pipe 80 is connected to the hydrant by means of the coupling 91 and the hose is connected to the right or left outlet pipe depending upon which side'the fire is located. Owing to these conditions, namely, that but one pump is used and the supply hydrant may be on one side or the other of the truck and the fire likewise may be on one-side or the other of the truck, of

necessity the inlet pipes cannot be positioned perpendicular to a linejoining the two centers of rotation of the impeller gears. In other words, the water may come into the pump from any of several directions, and the stream diverter must function regardless of the direction from which the water comes.

Assuming that the inflowing stream is coming from the right through the inlet pipe 80, it will be seen that the inertia of the infiowing stream would ordinarily tend to overflow the left hand impeller rotor which may be referenced 92, whereas there will be a deficiency of water supply to the right hand impeller rotor 93 owing to the inability of the water to negotiate the. curve 94. In other words, in order to have the pump balanced and working efiiciently it is necessary to supply both impeller rotors 92 and 93 with'substantially equal amounts of the inflowing fluid. To achieve this end there is positioned in the pump housing 86 a stream diverter 95 similar to the diverter 40 above described and in association with the stream diverter 95 the inlet pipes 80 and 81 have positioned therein the auxiliary stream dividers 96 and 97. The main diverter and auxiliary stream dividers combine to function as a multiple direction stream diverter, that is, the liquid stream is properly distributed to the impeller rotors regardless of the specific direction of the several directions from which the liquid stream may enter. The auxiliary stream If the dividers 96 and 9'7 are identical, and hence, the description will be limited to one end but considered as applicable to the other. The auxiliary stream divider 97 comprises a curved wedge shaped web mounted diametrically of the intake pipe 80 so as to equally and diametrically divide the portion of the intake pipe coextensive with the divider 97. The divider 97 is curved just sufficiently to divert substantially one-half of the inflowing stream to the impeller rotor 93 and the other half to the impeller rotor 92. The sides of 'the intake are curved complementally as at 94 and 98 with the stream diverter 9'7.

In operation, assuming the water to come through the right hand inlet pipe 80, the inflowing stream will be divided by the auxiliary stream divider 97. The left hand portion, owing to the cooperation of the divider and the curved face 98 of the intake, will be diverted to the impeller gear 92 as indicated by the arrows on the left. The other half of the infiowing stream will be diverted by the stream divider 97 angularly to the right as indicated by the .arrows Where the inflowing stream will be still further turned angularly to the right by the main stream diverter 95 and directed to the impeller rotor 93. In other words, the stream divider 9'7, in cooperation with the main stream diverter 95, directs substantially one-half of the infiowing stream to the impeller rotor 93, and owing to the curved faces, enable this portion of the stream to negotiate the curve 94 and thus insure a proportionately adequate supply of the inflowing liquid to the right hand impeller rotor 93. When the inflowing stream comes through the inlet pipe 81 the auxiliary stream divider 96 functions in a similar manner cooperatively with the main diverter 95 to insure substantially equal supplies of liquid to the right and left impeller rotors 93 and 92 respectively. Hence, regardless of whether the infiowing stream of liquid comes from one side or the other of the pump, the stream is properly divided, diverted, and distributed to the rotating impeller rotors.

From the above description it is evident that there is herein produced an opposed impeller rotor pump of the type essentially characterized in that the impeller rotors at all times intermesh along a progressively continuous non-intermittent area of contact which prevents entrapment or escapement of liquid and further, that the intake stream is diverted so as to fiow in a direction similar to that of the pathof rotation of the impeller gears to prevent impact between the rotating impeller rotors and the inflowing stream.

I claim:

1. In a pump comprising a housing having an inlet and an outlet, a pair of impeller rotors rotatably mounted'therein and having a plurality of teeth, each tooth of said rotors having a face a portion of which is an arc of a true circle having its center coincident with the center of rotation of the other rotor and another portion being an arc of a true circle of a different radius having its center on the center line of the tooth and tangent with the aforesaid arc and with the outer circumference of the said rotor on the center line of the tooth, and the opposite face of the said tooth being generated by a similar aforesaid face when the rotors are rotated together about their axis.

2'. In a pump comprising a housing having an inlet and an outlet, a pair of impeller rotors rotatably mounted therein and having a plurality of teeth, each tooth of said rotors having a face a portion of which is an arc 01' a true circle having its center coincident with the center of 5 rotation of the other rotorand'another portion being an arc of a true circle of a diflerent radius having its center on the center line 01' the tooth I ated by a similar aforesaid face when rotors are rotated together 60 about their axis.

AMOS v. JENSEN. 

